The present invention generally relates to heat exchanger coil apparatus and associated manufacturing methods, and in an illustrative embodiment thereof more particularly relates to helical fin/tube heat exchanger coil apparatus, representatively incorporated in a fuel-fired pool heater, and associated manufacturing methods.
In various previously proposed liquid heating applications the liquid to be heated is suitably circulated through helically coiled heat conductive tubing having secured thereto a longitudinally spaced series of heat conductive fins that encircle the tubing. A burner encircled by the helically coiled fin/tube heat exchanger coil generates hot combustion gases that are forced laterally outwardly through the coil and function to heat the liquid flowing through the tubing portion thereof. Various well known problems, limitations and disadvantages are commonly associated with this type of liquid heating apparatus.
For example, the burner-generated hot combustion gases tend to flow outwardly between the adjacent tubing coil pairs, via the gaps between the fin portions of the heat exchanger structure , thereby undesirably “bypassing” the tubing coils and lessening the overall heat transfer efficiency of the coil structure. In an effort to direct more of the hot combustion gases over the tubing, separate baffle structures have been secured to the fin/tube assembly, between the tubing coils, to channel more of the combustion gases directly over the tubing instead of through the spaces between the tubing coils. While this corrective measure tends to increase the heat transfer efficiency of the heat exchanger it undesirably adds to the weight, complexity and cost of the heat exchanger. It also undesirably increases the difficulty in constructing the heat exchanger, while still permitting a significant portion of the hot combustion gases to exit the heat exchanger without efficiently contacting the tubing portion thereof.
As can be seen from the foregoing, a need exists for a coiled fin/tube heat exchanger coil construction that addresses these problems, limitations and disadvantages associated with helically coiled fin/tube heat exchanger coils of the general type described above. It is to this need that the present invention is primarily directed.